WESTON, Mass.--(BUSINESS WIRE)--Apr 11, 2011 -
Biogen Idec (NASDAQ: BIIB) announced today positive top-line
results from DEFINE, the first of two pivotal Phase 3 clinical
trials designed to evaluate the investigational oral compound BG-12
(dimethyl fumarate) as a monotherapy in people with
relapsing-remitting multiple sclerosis (RRMS). Results showed that
240 mg of BG-12, administered either twice or three times a day,
met the primary study endpoint, demonstrating a highly
statistically significant reduction (p<0.0001) in the proportion
of patients with RRMS who relapsed at two years compared with
placebo. Both doses of BG-12 also met all of the secondary study
endpoints, providing a statistically significant reduction in
annualized relapse rate, in the number of new or newly enlarging T2
hyperintense lesions, in new gadolinium-enhancing (Gd+) lesions,
and in the rate of disability progression as measured by the
Expanded Disability Severity Scale (EDSS) at two years.

DEFINE was a global, randomized, double-blind,
placebo-controlled, dose-comparison study to determine the efficacy
and safety of BG-12 in people with RRMS. In addition to meeting the
primary and all secondary endpoints, initial data from the trial
showed that BG-12 demonstrated a favorable safety and tolerability
profile. The overall incidence of adverse events and serious
adverse events was similar among the placebo group and both BG-12
treatment groups. The safety profile was consistent with what was
seen in the published Phase 2 study of BG-12. Further analyses of
the DEFINE study are ongoing, and the company anticipates
presenting detailed data at a future medical meeting.

“The significant clinical responses seen in the DEFINE
study represent an important step forward in the development of
BG-12 for multiple sclerosis (MS),” said Douglas Williams,
Ph.D., Biogen Idec's Executive Vice President of Research and
Development. “We are very pleased with these data and believe
that BG-12 has the potential to offer MS patients a highly
effective oral treatment option with a strong safety
profile.”

Data from scientific studies indicate that BG-12 has the
potential to be distinctive by reducing the entry into and the
action of inflammatory cells on the Central Nervous System (CNS),
as well as potentially protecting CNS cells from oxidative stress
and death by activation of the Nrf-2 pathway.

BG-12 received Fast Track designation from the U.S. Food and
Drug Administration (FDA) in 2008. In addition to DEFINE, another
Phase 3 RRMS clinical trial, CONFIRM, is currently underway. This
study is evaluating BG-12 and an active reference comparator,
glatiramer acetate, against placebo on clinical relapse, magnetic
resonance imaging (MRI) measures of MS, progression of disability,
and safety. Results from CONFIRM are expected in the second half of
2011.

About the DEFINE Trial

DEFINE (Determination of the Efficacy and safety
of oral Fumarate IN rElapsing-remitting MS)
was a global, randomized, double-blind, placebo-controlled,
dose-comparison study to determine the efficacy and safety of BG-12
in more than 1,200 people with RRMS. The study evaluated two doses
of BG-12: 240 mg twice a day and 240 mg three times a day. The
primary objective was to determine if BG-12 is effective in
reducing the proportion of relapsing patients at two years.
Secondary endpoints included reduction in the number of new or
newly enlarging T2 hyperintense lesions and new Gd+ lesions as
measured by MRI, reduction in annualized relapse rate, and
reduction of disability progression as measured by EDSS. Additional
endpoints included the safety and tolerability of BG-12.

About Biogen Idec

Biogen Idec uses cutting-edge science to discover, develop,
manufacture, and market therapeutic products for the treatment of
serious diseases with a focus on neurological disorders. Founded in
1978, Biogen Idec is the world's oldest independent biotechnology
company. Patients worldwide benefit from its leading multiple
sclerosis therapies, and the company generates more than $4 billion
in annual revenues. For product labeling, press releases and
additional information about the company, please visit
www.biogenidec.com.

Safe Harbor

This press release includes forward-looking statements,
including statements about the development and commercialization of
BG-12 in MS. These forward-looking statements may be accompanied by
such words as "anticipate," "believe," "estimate," "expect,"
"forecast," "intend," "may," "plan," "will" and other words and
terms of similar meaning. You should not place undue reliance on
these statements. These statements involve risks and uncertainties
that could cause actual results to differ materially from those
reflected in such statements, including meeting endpoints in
clinical trials, obtaining regulatory approval, the occurrence of
adverse safety events, product competition, the availability of
reimbursement for our products, adverse market and economic
conditions, problems with our manufacturing processes and our
reliance on third parties, failure to comply with government
regulation and possible adverse impact of changes in such
regulation, our ability to protect our intellectual property rights
and the cost of doing so, and the other risks and uncertainties
that are described in the Risk Factors section of our most recent
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expectations and speak only as of the date of this press release.
We do not undertake any obligation to publicly update any
forward-looking statements.